Pathology The Fenton reaction leads to free radical generation when: A Radiant energy is absorbed by water B Hydrogen peroxide is formed by Myeloperoxidase. C Ferrous ions are converted to ferric ions. D Nitric oxide is converted to peroxynitrite anion. 💡 Explanation The Fenton reaction leads to free radical generation when: ✓ Correct Answer: C. Ferrous ions are converted to ferric ions.